Look at the setting and the character's state of mind, and then think about what you want the reader to see. Is there a descriptive symbol or two that works naturally within the scene to help foreshadow an event or theme, or create insight into the character's emotional plight?
The North Star
A four leaf clover
Rubbing a Buddha's belly
Finding a penny
The big half of a turkey wishbone
Finding a parking spot close to destination
Finding a meter with time on it
Red Chinese Lanterns
Blowing on a set of dice
The gift of Bamboo
Wishing well or fountain
The Hand symbol
The power of three
Salt tossed over shoulder
Throwing rice at weddings
Rain the day of the wedding
Finding money in a pocket you forgot was there
These are just a few examples of things one might associate with Luck . Some are more powerful than others. A four leaf clover is a strong symbol, and likely will not require reinforcement. However, the presence or gift of an egg may not foreshadow Luck on its own. Let the story's tone decide if one strong symbol or several smaller ones work the best.
*NOTE: This collection of good luck symbols is not complete, only some of the most common. Different cultures and parts of the world have their own luck totems.